- An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is calculated by dividing the system’s focal length by the diameter of the entrance pupil (“clear aperture”). The f-number is also known as the focal ratio, f-ratio, or f-stop, and it is key in determining the depth of field, diffraction, and exposure of a photograph. The f-number is dimensionless and is usually expressed using a lower-case hooked f with the format f/N, where N is the f-number.
- Minnesota State Fair: Origins and Traditions (mnopedia.org)
The Minnesota State Fair is a yearly celebration of agriculture, crafts, food, and community. In the twenty-first century, nearly 1.8 million people attend the twelve-day event every year, making it the second-largest state fair in the nation. The gathering is a Minnesota tradition that has more than earned its nickname, “The Great Minnesota Get-Together.”